Interaction between human serum albumin and blueberry anthocyanin

The interaction between blueberry anthocyanin and human serum albumin(HSA)was investigated by UV-visible spectroscopy and fluorescence spectroscopy.The results suggested that ACN had a strong ability to quench the fluorescence of HSA in a static manner.The calculated thermodynamic parameters showed that electrostatic forces and hydrophobic effects played an important role in the interaction between ACN and HSA.UV-visible spectroscopy and fluorescence spectroscopy revealed that the secondary structure of HSA,α-helix became loose and the microenvironment of tryptophan residues in HSA may change in the prescence of anthocyanin.Moreover,the spectral overlap integral between the donor emission and the acceptor absorption,the distance between donor and acceptor in anthocyanin-HSA were calculated at different temepraure,and based on the equations from Frster nonradiative energy transfer theory,the calculated data were:6.83×10-15 cm3· L · mol-1,3.12 nm(288 K);6.86 × 10-15 cm3· L · mol-1,3.18 nm(298 K);6.87 ×10-15 cm3·L·mol-1,3.22nm(308 K).Our data also indicated it would be highly possible that energy transfer from HSA to ACN occurred.The Frster nonradiative energy transfer may be one of reasons for quenching of the intrinsic fluorescence.